JPH01233812A - Multi-stage amplifier for microwave - Google Patents

Abstract

PURPOSE:To reduce number of elements of an oscillation prevention circuit by supplying a bias voltage to an input terminal of a transistor(TR) and providing a function of preventing oscillation to a short-stub applying matching and inserting the oscillation preventing resistor to the opposite side of the short- circuit face. CONSTITUTION:A function of preventing oscillation is provided to a short-stub 2 giving a bias voltage to the input terminal of the TR 1 and applying matching and the oscillation preventing resistor 3 is inserted to the opposite side of the short-circuit face. Since almost no current flows to the short-stub 2 supplying the bias voltage and applying matching, even when the oscillation preventing resistor 3 is inserted to the opposite side of the short-circuit face, no voltage drop exists and even when the constant is varied more or less to use the short- stub 2 with the oscillation preventing resistor 3 inserted thereto as the oscillation prevention, bias supply and matching, the characteristic is not affected by matching with a small change of the constant of other elements. Thus, the number of short-stubs and capacitors of the oscillation preventing circuit is reduced.

Description

[Detailed Description of the Invention] [Summary] Regarding a microwave multi-stage amplifier circuit that requires an oscillation prevention circuit having at least an oscillation prevention resistor and a short stub, the present invention relates to a microwave multistage amplifier circuit that can reduce the number of elements in the oscillation prevention circuit. For the purpose of supplying a multi-stage amplifier circuit, the short stub that supplies bias voltage to the input terminal of the transistor and performs matching has an oscillation prevention function, and an oscillation prevention resistor is inserted on the opposite side of the short side. composition.

[Industrial application field]

The present invention relates to an improvement in a microwave multistage amplifier circuit that requires an oscillation prevention circuit having at least an oscillation prevention resistor and a short stub.

There are two types of microwave multi-stage amplifier circuits: monolithic and bibride types, and field-effect transistors and bipolar transistors. It is desirable to be able to reduce the area and, in the case of a hybrid type, to reduce the number of assembly steps.

[Conventional technology]

A conventional example will be explained below using figures.

FIG. 4 is a circuit diagram of a conventional microwave multistage amplifier circuit.

In the figure, 01 to C12 are capacitors, C4 is an external capacitor installed outside the chip, R1 to R5 are resistors, and R1 is a capacitor.
, R4 is an oscillation prevention resistor, 10 to 12.13', 14
°, 15-17.18°.

19.20 is the line forming the distributed constant circuit, 30.3
1.32 is an open stub that forms an admittance and is open at one end, 40, 41.42", 43'
, 44 to 46 are short stubs that form an admittance and are shorted at high frequency by a capacitor, FET1 to FET3 are field effect transistors, v
1 indicates a bias voltage supply power supply, and 2 indicates a drain voltage supply power supply.

The figure below shows a multi-stage amplifier circuit using field effect transistors FET1-FET3 for use in the Ku band (12 GHz to 18 GHz). A bias voltage is supplied to the gate of the field effect transistor FETI via the line 12, and from the bias voltage supply power supply ■1,
Resistor R5゜ Short stub 43゛5 Field effect transistor FE72.FE7 via line 14° and 18"
A bias voltage is supplied to the gate of 3.

Also, short stub 4 from drain voltage supply power supply ■2
2', field effect transistor F via line 13'
A drain voltage is supplied to the drain of the ETI, and a short stub 44. A drain voltage is supplied to the drain of field effect transistor FE72 via line 15, and short stub 45. A drain voltage is supplied via line 19 to the drain of field effect transistor FET3.

Also, on the line, short stub, open stub, Ku
The gain characteristics in the band are flattened and impedance matching is performed.

Also, since oscillation may occur on the low frequency side of the band, a resistor R1 (50Ω) is used as an oscillation prevention circuit.

Short stub 41. The circuit consisting of the capacitor C2 and the circuit consisting of the resistor R4 (50Ω), the short stub 46, and the capacitor C12 are respectively connected to the field effect transistor FE.
It is provided on the gate side of TI, FET2, and FET3.

[Problem to be solved by the invention]

However, in conventional microwave multi-stage amplifier circuits,
An oscillation prevention circuit consisting of a resistor R1 (50Ω), a short stub 41, and a capacitor C2, and a resistor R4 (50Ω).
Short stub 46. Since an oscillation prevention circuit consisting of capacitor C12 is provided on the other side, in the monolithic type,
There is a problem that the chip area becomes large and the number of assembly steps increases in the hybrid type.

An object of the present invention is to provide a multistage amplifier circuit for microwaves that can reduce the number of elements in an oscillation prevention circuit.

[Means to solve the problem]

FIG. 1 is a block diagram of the principle of the present invention.

In a microwave multi-stage amplifier circuit that requires an oscillation prevention circuit having at least an oscillation prevention resistor and a short stub, as shown in FIG. A function for preventing oscillation is provided, and an oscillation preventing resistor 3 is inserted on the opposite side of the short surface.

[For production]

Short stub 2 that supplies bias voltage and performs matching
Since almost no current flows through , there is no problem because there is no voltage drop even if the oscillation prevention resistor 3 is inserted on the opposite side of this shorted surface, and the short stub 2 with the oscillation prevention resistor 3 inserted is used to prevent oscillation. Even if the constants are slightly changed for purposes such as bias supply and matching, the characteristics will not be affected as long as the constants of other elements are slightly changed for matching.

Therefore, the number of short stubs and capacitors in the oscillation prevention circuit can be reduced, the chip area can be reduced in the monolithic type, and the number of assembly steps can be reduced in the hybrid type.

〔Example〕

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 is a circuit diagram of a microwave multi-stage amplifier circuit according to an embodiment of the present invention, and FIG. 3 is a plan view of a chip in which the microwave multi-stage amplifier circuit of FIG. 2 is made into a monolithic type.

The difference in Fig. 2 from Fig. 4 is that the oscillation prevention resistor R
4 to the opposite side of the short side of the short stub 43 to reduce the short stub 46 and the capacitor 12, and for matching, line 13'', 14', 18' and the short stub 42° in FIG. Change the constant of 43゛ a little,
Line 13°14.18 and short stub 42.43
This is the point.

The point that the chip area can be reduced by doing this will be explained with reference to FIG.

FIG. 3 is a plan view of a chip when the microwave multi-stage amplifier circuit of FIG. 2 is made into a monolithic type. In the case of the conventional circuit, a short stub 46. A capacitor C12 must be provided, and this third
What could not fit into the 1.5 mm x 2.7 mm area of the chip shown in the figure now fits by reducing the number of elements.

Furthermore, the sensitivity is improved by reducing the number of elements.

Of course, in the case of a hybrid type, the number of assembly steps is reduced because the number of elements is reduced, and reliability is improved.

Note that the oscillation prevention resistor R1 is inserted on the opposite side of the short side of the short stub 40, and the short stub 41. The constants were slightly changed to reduce the capacitor C2 and use the short stub 40 for oscillation prevention, bias supply, and matching, and the constants of the nearby lines 1o, 11.12 and oven stub 30 were slightly changed for matching. Of course it's good too.

In this way, the number of elements can be further reduced, and in the case of a monolithic type, the chip area becomes smaller and the reliability is improved, and in the case of a hybrid type, the number of assembly steps is reduced by the reduction in the number of elements, and the reliability is improved. do.

Although the above description has been made in the case where the transistor is a field effect transistor, the present invention can of course be applied even in the case of a bipolar transistor.

〔Effect of the invention〕

As explained in detail above, according to the present invention, the number of elements in the oscillation prevention circuit can be reduced, and in the case of a monolithic type, the chip area can be reduced (and reliability can be improved), and in the case of a hybrid type, the number of elements in the oscillation prevention circuit can be reduced. As the number of parts is reduced, the number of assembly steps can be reduced and reliability can be improved.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the principle of the present invention. Figure 2 is a circuit diagram of a microwave multi-stage amplifier circuit according to an embodiment of the present invention. Figure 3 is a monolithic version of the microwave multi-stage amplifier circuit of Figure 2. FIG. 4 is a circuit diagram of a conventional microwave multi-stage amplifier circuit. In the figure, l is a transistor, 2.40.41~46.42', 43° is a short stub, 3, R1, R4 are oscillation prevention resistors, 10~20.13', 14° line, 30.31. 3
2 is an open stub, C1 to C12 are capacitors, R2, R3, and R5 are resistors, FETI to FET3 are field effect transistors, vl is a bias voltage supply power supply, and V2 is a drain voltage supply power supply.

Claims (1)

[Claims] In a microwave multi-stage amplifier circuit that requires an oscillation prevention circuit having at least an oscillation prevention resistor and a short stub, the short stub (1) supplies a bias voltage to the input terminal of the transistor (1) and performs matching. A multistage amplifier circuit for microwaves, characterized in that (2) has an oscillation prevention function, and an oscillation prevention resistor (3) is inserted on the opposite side of the short surface.